Add hasSelection() method

Author: karlvr

src/SketchField.jsx

@@ -457,6 +457,11 @@ class SketchField extends PureComponent {
     return discarded
   };
 
+  hasSelection = () => {
+    let canvas = this._fc;
+    return !!canvas.getActiveObject();
+  }
+
   /**
    * Remove selected object from the canvas
    */

types/index.d.ts

@@ -154,6 +154,8 @@ declare module 'react-sketch' {
 		 */
 		clear(propertiesToInclude?: ArrayLike<string>): string
 
+		hasSelection(): boolean
+		
 		/**
 		 * Remove selected object from the canvas
 		 */